If there were a giant wall around the Equator, how would the world work?

Factual Questions
1

So I just finished this book, Mainspring, by Jay Lake. It isn’t steampunk, maybe more… cogpunk? Anyway, the big conceit is that the Earth is clockwork. Its orbit is a big brass thing in the heavens, and there’s a huge enormous wall around the equator with gear teeth on top, and that’s how it runs.

Obviously, the clockwork Earth is not like our Earth, but as a thought experiment, let’s say there was a giant (miles high, higher than Everest, enough that if your clockwork God hadn’t put air at the top you couldn’t go there) wall all around the Equator. It’s extremely difficult to cross and almost nothing does cross it.

If there were humans on both sides, would the Guns, Germs, and Steel effect screw the Southern people over? (Would they be better off, only less technologically advanced?) Remember, nothing makes it over - no plants, no animals, etc. unless your clockwork God puts them there.

Could the oceans “work” with a wall there? Obviously the currents would be extremely different.

How would that affect the weather? Would the climate of the continents be roughly the same, or would everything be completely different? Surely the Gulf Stream would not warm Britain and other parts of northern Europe, right? What about the way hurricanes form off the coast of western Africa - disrupted, I’m sure. What would the climate of such an Earth even begin to look like?

Tides? The moon has its own track and gear.

Is there anything else that would be dramatically affected? Plate tectonics? (I suppose we can assume the Wall goes all the way down, otherwise I don’t see how we could go around the Sun on it.)

2

Since the Gulf Stream originates in the Gulf of Mexico (well north of the Equator), I’m guessing it would.

3

Since air currents wouldn’t be crossing the equator, the climates in each hemisphere wouldn’t be tempered by the other. Summers would be much hotter, and winters would be much colder.

4

Yeah, but it’s not like it operates in isolation, does it?

5

Do both hemispheres get the same amount of rainfall?

Because I’m thinking that if the amount wasn’t equal, over the course of millenia one would have all its oceans dry up, while the other would have them rise and rise, covering its the landmass until, eventually, it would transform the equatorial wall into an equatorial waterfall.

6

Wouldn’t both hemispheres both having their own water cycle essentially keep things at an equilibrium? I mean, rain doesn’t make itself, and the atmosphere doesn’t make it over the Wall except, I assume, in that tiny amount that you need, if you’re a protagonist, to go climbing.

7

If the wall is a disc that goes all the way through the Earth, it would have to be made of tempered unobtainium to resist being broken by Earth’s gravity and tectonic forces. But assuming that’s the case, I would expect the base of the wall to be very seismically active, as the plates grind against it from both sides. It would probably be flanked with huge volcanoes all the way around.

8

How would that be possible?

If the two sides are seperated as you say, humans would have had to evolve twice, which seems quite unlikely.

If on the other hand, the world came about by “creationism” and God put humans on both sides, then why bother asking scientific questions about the world at all… the answer to them all is “magic man done it”.

9

If the atmosphere can’t pass the wall (i must have missed that part of the OP), then yeah, you’re right.

10

Well suppose it’s a mixture of the two… ancient astronauts brought man to Earth and dropped us on both sides of the wall.

Might one not get a similar barrier effect if the Earth were rotating a lot faster, exaggerating the equatorial bulge?

11

I’m thinking that this giant wall would, in a scientific world, eventually develop cracks and instabilities. A large single piece of metal would be subject to a great number of local temperature variances; its peaks would be in a vacuum, exposed to solar radiation, but its base would be at the ocean floor. Part of the wall may well cross bitterly cold mountain ranges.

If the wall were metal it should communicate heat (if slowly) from one side of the wall to the other. Such a large mass might stabilize the temperature of the water, I suppose, depressing currents.

Yeah, I don’t know how much science you can apply to it. That’s what makes me want to read this book. :slight_smile:

12

In a hypothetical world, it’s unlikely that humans would evolve even once. I think the idea behind this sort of thought experiment is that the wall is conceptually added to the real Earth, and we try to figure out what would follow from that one change.

So if we want to establish a geological history for this thing, it makes the most sense to say that the Earth developed as in real life for a certain length of time, and then a magical being showed up, added the wall, and left.

If the wall was added before life originated, and assuming the wall didn’t disrupt conditions enough to prevent life from forming, then life may have formed on only one side. The question then is whether living things could cross the wall and colonize the other side. You might have an Earth-like ecosystem on one side and only fungus on the other, spawned by a few lucky spores that managed to blow across on high-altitude winds. But if humans arise on the Earth-like side, they could at some point get over the wall and establish colonies.

On the other hand, if the wall was added after humans spread to all the continents, but before civilization, it would only have been in place for some thousands of years–not long enough for wildly divergent evolution to take place.

Depending on when you suppose the wall came into being, you could have humans on one side and dinosaurs on the other, etc.

13

Well, in the book at least we’re obviously dealing with a Created world, since their god is literally a watchmaker. There’s not really a lot of room for straight out atheism when you can see the track the gears of the world grind on. I’m just wondering what a realistic interpretation of the idea would be once you stick the wall there and then pretend you’ve got a natural world.

14

It’s the Well World! Yoyu’ve got the non-carbon=based life forms on the other side! You need a rocket to get over to the other side!

Or, no – it’s The Wall Around the World! When you try to cross it, it turns out to be Moebius-strip-like, and have no other side:

15

Obviously the foundations for the wall would have to be Mega deep but would it be possible for the inhabitants to tunnel beneath it or failing that if they developed rocketry they could cross the wall with sub orbital flights.